Abstract
Predicting evolution of small node‐negative breast carcinoma is a real challenge in clinical practice. The aim of this study was to search whether qualitative or quantitative DNA changes may help to predict metastasis of small node‐negative breast carcinoma. Small invasive ductal carcinomas without axillary lymph node involvement (T1T2N0) from 168 patients with either good (111 patients with no event at 5 years after diagnosis) or poor (57 patients with early metastasis) outcome were analyzed with comparative genomic hybridization (CGH) array. A CGH classifier, identifying low‐ and high‐risk groups of metastatic recurrence, was established in a training set of 78 patients, then validated, and compared with clinicopathological parameters in a distinct set of 90 patients. The genomic status of regions located on 2p22.2, 3p23, and 8q21‐24 and the number of segmental alterations were defined in the training set to classify tumors into low‐ or high‐risk groups. In the validation set, in addition to estrogen receptors and grade, this CGH classifier provided significant prognostic information in multivariate analysis (odds ratio, 3.34; 95% confidence interval 1.01–11.02; P = 4.78 × 10^−2^, Wald test). This study shows that tumor DNA contains important prognostic information that may help to predict metastasis in T1T2N0 tumors of the breast. © 2010 Wiley‐Liss, Inc.